The invention relates to a driver assistance system for driver assistance for consumption controlled driving.
There exist a plurality of driver assistance systems that help the driver, for example, by navigation, by controlling the longitudinal dynamics or by means of warnings while he is driving. Some driver assistance systems also consider to some extent measures for reducing the fuel consumption. For example, DE 10 2007 006 501 describes an automatic cruise control system that intentionally allows larger deviations in order to reduce the fuel consumption. Furthermore, there already exist navigation systems that offer the driver the possibility, when entering a destination, to choose a route from a selection of efficient routes.
It is an object of the invention to improve a driver assistance system of the above-mentioned type with respect to further reducing the fuel consumption while simultaneously taking into account the intentions of the driver.
The invention achieves this and other objects by providing a driver assistance system for assisting the driver in consumption controlled driving. The system includes an electronic control system and feedback functions. The driver assistance system is characterized by a proactive assistant consisting of a control system and a display as the visual feedback function. The control system evaluates the speed and distances as a function of the route data of a predetermined route combined with current vehicle data such that the exact time or the route point, after which a predetermined speed in a defined distance, can be reached in overrun mode and/or in coasting mode. Upon reaching this exact time or this route point, the control system sends by way of the display at least one driving recommendation to release the accelerator pedal of the vehicle.
The invention is based on the following considerations, knowledge and ideas.
When a vehicle driver plans a route with the current generation of navigation systems, the navigation systems provides the driver with the expected trip duration and distance to the destination as the selection criteria for various routes. An improved efficiency oriented navigation system (for example, the future BMW green driving assistant) can offer the automobile driver a tool that also informs him about the fuel consumption on the route and, thus, helps him to select a fuel consumption optimized route.
In the course of planning a route before the start of a trip, the driver can compare the routes that offer the shortest driving time or the lowest fuel consumption. In order to help the driver make a decision, the green driving assistant lists not only the known criteria, arrival time and distance, but also the expected amount of fuel that will be saved. As a result, it is easy to decide whether the potential reduction in fuel consumption is worth a somewhat longer driving time.
In addition, while driving, the green driving assistant offers options to ensure that the driver will reach his destination even more efficiently and comfortably. The assistant alerts the driver as soon as it registers that the remaining range is insufficient to reach the desired destination with the current driving style and route. The system shows whether the fuel consumption could be optimized by activating the ECO mode (for example, by activating an ECO mode button) or by choosing another route, in order to reach the destination nevertheless without having to stop to refuel and, thus, without the associated loss of time.
If the driver wants to continue with the same driving style, the gas station assistant of the green driving assistant allows the timing of a stop at a gas station to be planned into the route. When offering the gas stations, the system takes into consideration whether the driver prefers a particular gas station company because it holds a customer loyalty card or a particular fuel and how great a detour would be involved due to the stop at the gas station. As soon as the driver has decided on a gas station, this station is entered into the navigation system as an intermediate destination, and the route calculation is adapted accordingly.
A driving and/or driver profile, learned by the navigation system, serves as the basis for calculating the range, arrival time and the reduction in fuel consumption for a route. In this context reference is made to BMW's patent application DE 10 2009 039 092, which has not been published yet. For example, an appropriate driver and/or vehicle adaptive algorithm in a control unit can learn the typical fuel consumption preferably by means of a predetermined learning route (of, for example, about 500 km), which the green driving assistant uses to plan each new route.
As stated above, the vehicle may have, in principle, a selector button (ECO mode button), which offers the driver at the touch of this button a number of options to ensure a fuel optimized driving style. A holistic approach comprising the drive configuration and the display concept offers the driver the possibility of reducing his fuel consumption in a number of different ways. The combination of the “proactive driving assistant” and “coasting in neutral” (see below) significantly increases the potential to save fuel.
Therefore, the route data from the navigation system and the measures for an efficient driving style can be combined to save fuel. In accordance with the invention, the drive configuration, the display concept and the proactive driving assistant are the center of interest in the considerations and are explained by and large in more detail below.
Drive Configuration According to the Invention
When the driver activates the ECO mode by way of the selector button or another switch (for example, in the center console of the dashboard), the invention provides that the power output available from the engine remains the same, but its performance characteristics change. The accelerator pedal characteristics and switching characteristics of the automatic transmission and/or the shift point display of manual transmissions are adapted in order to facilitate a more efficient driving mode.
The accelerator pedal characteristic is a key factor in the drive configuration. The vehicle runs in ECO mode up to an accelerator pedal deflection (or rather a gas pedal deflection) of preferably about 70 percent. That is, an increase in deflection results in an increase in the fuel optimized power output by suitably activating, in particular, the actuators of the internal combustion engine. If the driver leaves this range, then the increasing pedal angle results in a transition to the maximum power output. The accelerator pedal characteristic is configured such that this transition is intuitively easy to understand and can be found at any time. Consequently, in normal driving mode, it is possible to obtain a significant advantage in fuel consumption. However, if desired, in certain special situations, such as driving onto a freeway or passing a vehicle, it is possible to request the increased acceleration that is required for such situations.
Display Concept According to the Invention
If the driver switches over into the ECO mode, the displays, preferably modified displays, in the instrument cluster of the dashboard can be activated, thus motivating the driver to drive in a more efficient style. At the same time preferably an accelerator pedal recommendation is displayed, for example, instead of the current fuel consumption. A highlighted area (for example, in blue or green) symbolizes the efficient accelerator pedal range. If the driver leaves this range, then the increasing accelerator pedal angle marks a transition to the maximum power output. In addition, the driver may have the option of defining a customized ECO maximum speed (for example, between 90 km/h and 130 km/h). If the driver exceeds this speed, he receives a reminder in the form of a so-called “ECO tip” on the display. Advantageous improvements for broadening the idea of an ECO tip concept are explained in the exemplary embodiment. The term “ECO tip” is defined as a suggestion to the driver to execute a specific action for the purpose of reducing the fuel consumption.
The ECO mode enables the driver to save fuel and increase the range. This difference in the range is transmitted preferably in a new display in the form of a “bonus range display”. In this way the driver is given direct feedback about his success in saving fuel and is rewarded with bonus kilometers. The longer the driver continues to drive economically in ECO mode, the higher the number of bonus kilometers will be.
In addition, the driver can have the display show him a history of his fuel consumption. He can see the mode, in which he has been driving, and how high or low his average fuel consumption is. The “experience technology” monitor, which can be displayed, when desired, gives visual expression to the action that has been taken to ensure an efficient driving style. The active systems are highlighted in an abstracted vehicle diagram, while the text provides more detailed information on the status and effect of each function. In this way the customer can find out which systems are activated and when they are activated, for a better understanding and knowledge of the technology.
For example, it is possible to record a variety of additional data about the trip using a mobile terminal device, and the efficiency of a trip can also be analyzed outside the vehicle. One example of such an application is the concept of an iPhone App under the name MINIMALISM Analyzer that is based on MINI Connected. It provides the customer in a game-like format with feedback about how efficiently he is accelerating and how carefully he is decelerating in advance and how well he is changing gears. The MINIMALISM Analyzer edits the data in a simple and informative way. At the destination it enables the application to analyze the trip, give tips for reducing the fuel consumption and allows the user to compare himself in a Community Ranking.
In addition, the ECO mode has the functions active coasting in neutral and proactive driving assistant that enable an even more efficient driving style.
Proactive Driving Assistant According to the Invention
In the ECO mode the “proactive driving assistant” is also active. It helps the driver to anticipate future driving situations and to make optimal use of the kinetic energy of the vehicle. The vehicle knows the speed limits, tight curves and turn-offs and calculates the exact time at which the driver can let the vehicle coast efficiently. The vehicle knows the appropriate situations due to the data from the navigation system; the pointer appears, for example, in the instrument cluster on the dashboard and/or in the head-up display, thus preferably in the driver's direct line of vision. The proactive driving assistant considers the deceleration behavior, based on current vehicle data and road profile data, and also takes into consideration whether the vehicle has the active coasting in neutral function (see below). The proactive driving assistant allows the vehicle to coast at the right times and, in so doing, save fuel without impeding the vehicles following behind. In addition, future versions of the proactive driving assistant will use current traffic and route data from the so-called “learning navigation system” (see below) in order to optimize its prediction.
Active coasting in neutral is a function that is intended for automatic vehicles and that is especially advantageous in conjunction with the ECO mode. If the driver takes his foot off the gas, the transmission automatically disconnects the drive connection between the motor and the transmission. The only forces now braking the vehicle are the rolling resistance and the air resistance. With an appropriately forward looking driving style the frictional losses in the drive train can be eliminated and, in so doing, save fuel. When the driver gives the brakes a light touch, the vehicle engages again automatically and continues to slow down in overrun mode with the so-called “engine brake.” Even if the driver eases off the brake again, the vehicle continues to coast down to lower speeds, and the brake energy regeneration continues to save fuel. If the driver accelerates again and then takes his foot off the gas again, the vehicle coasts again. Needless to say, all driving control and stability systems remain active when the vehicle is in coasting mode. The active coasting mode uses the kinetic energy that already exists in the vehicle.
Although the engine continues to consume fuel in the active coasting mode, the fuel consumption in neutral mode is relatively low. The fuel consumption advantage of the active coasting in neutral mode over the simple engine braking lies in the fact that active coasting avoids frictional losses and—when used with a proactive driving style—can be maintained over longer distances, because the vehicle rolls much further when it is coasting than when slowing down under the engine brake.
In addition to the preset configurations, the scope of the ECO mode can be customized. For example, the ECO mode functions—ECO maximum speed and active coasting in neutral—can be turned on or off individually. Furthermore, the driver has the option of selecting a specific efficiency program that is intended for the interior comfort and that includes a climate program and a special management of the electric consumers. Active coasting in neutral can enhance and/or supplement the proactive driving assistant in an advantageous way.
In addition, it must be pointed out that the ECO mode measures for the drive configuration, the display concept and the proactive assistance including the ECO tips could in principle always be active even without the ECO mode button or could also be automatically activated as a function of certain conditions.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.